If a eukaryotic cell undergoes glycolysis in the absence of oxygen, which of the following outcomes regarding the balance of NAD+ and ATP is correct?
1. NADH produced in glycolysis is reoxidised to NAD+ electron transport chain, maintaining glycolysis.
2. Fermentation pathways regenerate NAD+, allowing glycolysis to continue with net 2 ATP per glucose.
3. No NAD+ regeneration occurs, leading to immediate cessation of glycolysis after a few cycles.
4. Fermentation pathways generate additional ATP beyond the 2 ATP of glycolysis.